Dourle-walled electrically-heated vessel



July 9, 1929. KARLS N 1,720,045

DOUBLE WALLED ELECTRIGALLY HEATED VESSEL Filed Feb. 25, 1928 2 Sheets-Sheet 1 inventor?- J f WW 2% July 9, 1929. J. H. KARLSON DOUBLE WALLED ELEGTRICALLY HEATED VESSEL 7 Filed Feb. 25, 1928 2 Sheets-Sheet 2 rium.

.Il lll Patented July 9, 1929.

' .mmus a. mason, orcnrcaeo, nmivors.

DOUBIE-WALLED ELECTBICALLY-HEATED Application filed February 25, 1928. Serial No. 856,887.

This invention relates to vessels having electric resistance means embodied in their construction for the purpose of rendering them self heating, and in the construction of which, for the purpose of developing a heating chamber to receive the resistance medium, there are usually two telescopically assembled walls. Even with thoroughly soldered or brazed joints between the several members of a double walled vessel of the kind referred to, it is exceedingly difficult, if not impracticable, to avoid condensation of moisture within the heating chamber, and for this reason it is important, in the construction of such vessels, to not only avoid the use of plastic or'fabricated insulation that is absorbent as to moisture, but to make the capacity of the heating chamber as small as practicable consistent with the convenient and eflicient location of the heating unit; also to envelop the resistance element as snugly as practicable even when the insulation material is impervious to moisture; and in meeting all these conditions it is, of course, desirable to provide a construction of electric resistance heating unit that will be efficient and durable in service and economical with respect to the materials and time consumed in making and applying it to the vessel, as well as in assembling the two walls of the vessel and connecting the resistance element to terminals on the outer wall after the resistance unit has been applied to the inner wall.

The object of the present invention is to provide a construction of electrically heated vessel that will meet all the conditions above enumerated, and serve other advantages which will be apparent from the detailed description of the invention. Accord ingly, the invention proceeds upon the principle of utilizin three or more sheets of insulating material, to-wit, a base sheet, a

'core sheet, and a cover sheet, of such form that when assembled with the core sheet wound flat with resistance wire and confined between the two other sheets, and all the sheets are united at one end of the unit while they are left free at their other ends, the unit thus produced will be of such dimensions and inherent flexibility that it will readily conform to the exterior surface of the internal wall of the vessel and can be secured in position there by a metallic clamping band surrounding the unit and drawn together thereon, by means of a wedging nuts of the usual pin-terminals which protrude through the outer wall of the vessel. In the accompanying drawing, in which the preferred embodiment of the invention is shown by way' of illustration Figure 1 is a vertical axial section through a self heating vessel in which the several features of the present invention are embodied.

Figure 2 is a. section on the line 2"- x of Figure 1.

Figure 3 is a section on the line 3 3 of Figure 1.

Figure 4 is a detail view. partly in section of the electric resistance heating element separated from the vessel and in extended form.

Figure 5 is a section on the line 5" x of Figure 4. p

Figure 6 is a view corresponding to the lower end of Figure 1 showing a modified construction incident to the assembly of the walls of the vessel.

Figure 7 is a detail view of the wedging means for clamping the-resistance unit to the inner wall of the vessel; and

Figure 8 is a detail view illustrating the method of anchoring the ends of the resistance element.

1 represents the body of the vessel, 2 the inner wall of the heating chamber preferably made integral with the body 1, 3 the outer wall or jacket which surrounds the wall 2 and is of such dimension as 'to leave a heating chamber 4 between the walls, and 5 indicates the resistance element generally.

As shown in Figures 4 and 5, the resistance unit comprises a base sheet 6, a core sheet 7, and a cover sheet 8, the core sheet 7 selves, as shown more clearly at 10 in Figure 5, and with the free end of the doubled portions fixed by binding clips 12; and in assembling, the two outer sheets with the intermediate core sheet, all preferably preturn-bends that adapt them to be'grip 1 member 2 and outer member already ends suitable seats tive walls,

material, if necessary in securing a sufficient- .ly substantial core upon which to wind the resistance wire. Having applied the heating unit, developed as described, to the wall 2, the unit is secured in place thereon by means of a metallic clamping band 14, the s aced ends 15 of which are constructed wit r3- 7 and the ends are rawn together tig tly about the unit, and the unit is thus pressed into intimate contact with the wall 2 by means of a wedging cli 16 having coacting return-bendsides 17 t at engage with the ends 15 of the band. Clip 17 constitutes a very effective and very economically applied means of developing desired pressure of the band 14 upon the unit 5.

To electrically expose the ends of the heating 'unit on and in convenient form for connecting with conventional circuit closing means, the ends ling ends 18 of.

10 are connected with co aluminum or other semi-so t metal by passing the ends 10 through integral straps 19 struck up from the metal of the couplers 18, and the free ends then caught beneath thelock nuts 20 on terminal post 21 which protrude through the outer wall or jacket 3. The means for mounting the terminal pins 21 in the wall 3, preferab y consist of outer nuts 22 having neath nuts 22 on the outer wall 3, lava bushings 25 surrounding the pins 21 protruding throu h wall 3 but seating against aluminum or so metal washers 26, and the nuts 20, referred to, on the inner ends of the terminal pins seating through'means of their washers 27. .It sometimes happens that through carelessness in abandoning the vessel to the heating, current too long without any liquid in the vessel, the vessel becomes .excessivelyehot, air pressure within the heating cham r increases to a considerable deee, and the joint between jacket 3 and the bbdy 1 is jeopardized. To guard against such a contingency and avoid hazard, inner 3 are physically connected through their bottom walls by means of a bolt 28 havin at its respective rovi ed on the respecand pre erably having its head seated at 29in the bottom 30 of the outer member and its nut 31 mounted in a nut pocket 32 which is spot-welded or otherwise are riveted together at' theexterior of the vessel.

of these couplers 18 are secured to the inner surface of the bottom 33 of theinner member 2 without, however, penetrating said bottom 33. Nut pocket 32 is 0 en laterally to admit the nut 31 within 1t ut conforms sufiiciently to the contour of the nut to prevent the latter from rotating when the b0 t 28 is screwed up to proper tension.

As shown in Figure 6, bolt 28" may be seated at its upper end in a seat 29', and have its nut 31" caught beneath the bottom 30 of the outer member 3. In Figure 1, the bottom 33 of the inner member 2 and bottom 30 of the outer member 3 are formed integrally with the said members, preferabl by the process of splining the members. In igure 6, bottom 30 of the outer member 3" is formed separately from the latter. Except for sli htvariation in the disposition of the coup er members 18 in Figure 6, the 85 construction and arrangement of the terminal is identical with that described with reference to the other figures.

I claim: 1

1. A heating unit for application to curv- 9o ing walls of electrically heated vessels, comprising a base sheet of insulating material, a core sheet of insulating material carrying resistance wire, and a cover sheet of insulat ing chored to one of said sheets and protruding for connection with an electric circuit when the unit is coiled about a cylindrical surface. 3. A heating unit for application to curvwalls of electrically heated vessels, comprising a base sheet of insulating material, a core sheet of insulating material carrying resistance wire, and a cover sheet of insulating material,-said sheets being connected together at one end and having their other ends free; the ends of the wire being anchored to said core sheet and protruding for connection with an electric circuit when the unit is coiled about a cylindrical surface.

4. A heating unit for electrically heated 12o vessels, comprising a base sheet of insulating material, a core sheet of insulating material carrying resistance wire, and a cover sheet of insulatin material, said sheets being connected toget er at one end and having their other ends free; the ends of the wire being anchored to one of said sheets and protruding for connection with an electric circuit when the unit is coiled about a cylindrical surface; the protruding portions of the wire being coupled and lapped upon themselves and having their lapped portions secured by the anchorage. i

5. A heating unit for electrically heated vessels, comprising a base sheet of insulating material, a core sheet of insulating material carrying resistance wire, and a cover sheet of insulating material, said sheets being connected together at one end and having their other ends free; the ends of the Wire being anchored to said core sheet and protruding,

for connection with an electric circuit when the unit is coiled about a cylindrical surface; the protruding portions of said wire being lapped upon themselves, and clips being provided for holding the free ends of the lapped portions to the body of the wire.

6. In an electrically heated vessel, a wall to be heated, a heating unit comprising a multiplicity of sheets of insulating material, of which an interior sheet has wound upon it a resistance Wire, said sheets being united together at one end of the unit and left free to slide one upon the other at the other end of the unit and the unit thus provided being con formed circumferentially to the said wall, and a clamping band surrounding said unit and pressing it intimately against the wall.

7. In an electrically heated vessel, a wall i to be heated, a heating unit applied circumferentially to said wallcomprising a resistance element, and insulating sheets on opposite sides thereof, a clamping band surrounding said heating unit and having spaced ends, and a wedging clip engaging said spaced ends and slidable thereon transversely of the band and thereby drawing the hands together upon the heating unit.

8. In combination with the wall of a vessel, a heating unit applied circumferentially to said wall, a clampingband surrounding said heating unit, said band having divergent spaced ends constructed for engagement with a binding clip, and a binding clip having divergent sides engaging said ends and slidable relatively thereto to draw the band together upon the heating unit.

9. In an electrically heated vessel, a heating unit applied circumferentially to the wall of the vessel and including a resistance wire, a pair of coupling members clipped to the ends of said wires, and terminal posts secured to the ends of said coupling members and protruding through a wall of the vessel.

Signed at Chicago, Illinois, this 23rd day of February, 1928.

JULIUS H. KARLSON. 

